Zannichellia (common name Horned Pondweed) is a genus of submerged aquatic flowering plant.

Spiked water-milfoil, blunt-leaved pondweed, horned pondweed are also reported in the marsh land, apart from rare species of flowering-rush, water-violet and marsh stitchwort.

Near Desire Parker's home in Ledyard, hemlocks and beeches fringe Poquetanuck Cove, and a rare plant, horned pondweed, flourishes in the marsh.

Zannichellia palustris, (Horned pondweed), is a plant found in fresh to brackish waters in the United States (especially in the Chesapeake Bay), Europe, and South America.

The more saline flashes are fed by natural brine springs and contain a range of species tolerant of brackish water, for example, Spiked Water-milfoil Myriophyllum spicatum, Fennel-leaved Pondweed Potamogeton pectinatus and Horned Pondweed Zannichellia palustris and the green alga Enteromorpha intestinalis.